RICHMOND - Democrats in the General Assembly are trying to curb the power of the state's attorney general to subpoena public universities in an effort intended to limit inquiries like the one Attorney General Ken Cuccinelli II is conducting at the University of Virginia.

Under a 2002 statute designed to catch government employees defrauding the public of tax dollars, Cuccinelli (R) has demanded that the university turn over documents and e-mails related to the work of Michael Mann, a former university climate scientist whose research showed that the Earth has been warming.

Cuccinelli has said he wants the documents, including grant applications and e-mails exchanged between Mann and 39 other scientists and university staffers, to help determine whether Mann committed fraud by knowingly skewing data as he sought publicly funded grants for his research.

Cuccinelli's demand has pleased conservatives, who say that global warming is a hoax, but has outraged many academics, who say he is smearing an honest researcher because he does not approve of his findings.

Several previous investigations of Mann's work, including one by Pennsylvania State University, where Mann has worked since 2005, found that although his research conclusions were open to debate, there was no evidence that Mann engaged in efforts to falsify or suppress data.

U-Va. has been fighting the subpoenas in court, alleging that Cuccinelli's request infringes on the academic freedom of its faculty.

As the litigation proceeds, some legislators have proposed changing the law to make it harder for the attorney general to issue such civil subpoenas.

A bill sponsored by Sen. J. Chapman "Chap" Petersen (D-Fairfax) would shield academic work at universities from being subject to civil investigative demands by the attorney general.

A broader effort sponsored by Sen. A. Donald McEachin (D-Richmond) would require that in civil cases, the attorney general file a lawsuit that can be reviewed by a judge before he is able to issue subpoenas.

If the bills pass the Democratic-led Senate, they are unlikely to be approved by the House of Delegates, where the GOP holds a strong majority.

Still, they afford Democrats a forum for hammering the controversial attorney general over the U-Va. subpoena, which they consider an area of vulnerability with moderate voters.

"Jefferson would be turning in his grave to see what was coming from Richmond because of Attorney General Cuccinelli's efforts to capture private correspondence within faculty and staff at the University of Virginia," said Del. David J. Toscano (D-Charlottesville), who is co-sponsoring the bill and whose district includes the university, which was founded by Thomas Jefferson. "If people are concerned about government intrusion into your private life, you ought to be very concerned about what the attorney general is attempting to do in this case."

Toscano was speaking at a news conference held by sponsors of the bill Tuesday.

In an e-mail, Mann said he was grateful to the legislators for pressing the issue and said he hoped the legislative action will give Cuccinelli "some second thoughts about continuing to waste their time and resources attacking well-established science."

"It isn't just scientists and academics who see the problem with Cuccinelli's investigation, but also some of Cuccinelli's more responsible colleagues in state government," Mann said.

Cuccinelli spokesman Brian Gottstein noted that Virginia's law is modeled on a federal statute that has also included subpoena power since 1986. He said removing the power might jeopardize Virginia's compliance with another federal law that allows states to increase the share of money they recover when they win fraud cases.

"The CID [Civil Investigative Demand] provides a subpoena authority that allows the attorney general to investigate allegations of fraud to determine whether fraud may have occurred, and if so, to what extent," he said in a statement. "The information gathered allows the attorney general to decide whether a case should go forward or whether he should move to dismiss the complaint. If the CID authority is taken away, that leaves the attorney general's office only with the option of filing suit and obtaining the additional information through the discovery process once the case is filed."

Some top Republicans in the House of Delegates said the bills are unlikely to find favor there.

"I think what our attorney general is doing is well within his power - I agree with it," said Del. David B. Albo (R-Fairfax), chairman of the committee that would consider the proposals. "Would I have chosen that as a big thing to spend my time on? Probably not. But it seems to me that if you're the attorney general and you ask a government agency to give you stuff, they're supposed to give it to you."

House Speaker William J. Howell (R-Stafford) said he would not support efforts to restrict Cuccinelli's powers.

"I think the attorney general is doing a very good job, and I'm not particularly interested in curbing his power at his point," he said.

An Albemarle County judge quashed one version of the subpoena in August, ruling that Cuccinelli had not properly explained his rationale for thinking fraud might have been committed. But Cuccinelli reissued the request, and the issue remains in litigation.

In his reissued CID, the attorney general wrote that he seeks the documents because Mann wrote two papers on global warming that "have come under significant criticism" and that Mann "knew or should have known contained false information, unsubstantiated claims and/or were otherwise misleading."

"Specifically, but without limitation, some of the conclusions of the papers demonstrate a complete lack of rigor regarding the statistical analysis of the alleged data, meaning that the result reported lacked statistical significance without a specific statement to that effect," the new CID alleges.